It is known in the prior art to provide an occupant protection system in which the position of the occupant is monitored to determine the preferred measure of air bag deployment. Accordingly, the prior art shows that the seating position of the occupant relative to the corresponding safety devices such as the air bag are monitored continuously by sensors and evaluated in a computer-supported system in order to derive the time and the extent of the protective measures to be initiated under certain predetermined vehicle conditions. The sensing of the position of the occupant is achieved by means of distance and positioning measuring devices which emit beams and receive them. A disadvantage to this prior art, however, is that the beams of the distance and position measuring devices directly scan the occupant or measurement. For example, incorrect measurement readings could be taken if an object, such as a map or newspaper, is located between the sensors and the occupant, since the measuring device cannot distinguish between the identity of different measurement surfaces.